The invention is concerned with the use of xylite (C.sub.5 H.sub.12 O.sub.5) for cooling injured parts or areas of a human or animal body, and a cooling pack in which the xylite is preserved in a particularly advantageous and ready-for-use form.
In medical practice, it is known and usual for injured parts and areas of a body to be cooled below the usual body temperature as quickly as possible after the injury has occurred, in order to slow down the metabolism in the cells in the region of the injury until treatment can be applied, and to eliminate reactions which are disadvantageous in regard to the heating process. Thus it is known for the region of the body affected by injury to be cooled with iced water in the case of sprains or ligament strains but also in the case of open wounds. Further, it is known for example for parts of a human body which have been cut off in an accident to be kept at the lowest possible temperature above freezing point until an operation (replantation) can be performed (see the applicants' German Offenlegungsschrift (laid-open application) No. 29 49 909).
In many cases, it is not possible effectively to cool the injured part of the body as quickly as possible after an injury has been suffered, due to the absence of a suitable cooling agent. This frequently applies even in regard to first-aid stations, ambulances and the like as ice for making iced water is available only when it can be constantly stored independently of the outside temperature. However, a serious problem is in particular the fact that, when dealing with open injuries and wounds, cooling cannot be considered when there is the fear of danger of infection or other damage caused by the cooling agent. The result of this is that open injuries, for example open fractures of limbs, cannot be cooled by means of water which possibly comes directly into contact with the wound.
There is therefore a need for a cooling means or agent for cooling injured parts or areas of a body to be held in preparation, at least in accident stations, ambulance vehicles and the like, which cooling means or agent can be stored unrestrictedly and irrespective of the outside temperature without separate cooling arrangements, and which does not give rise to any danger of infection or poisoning even in the event of its coming into direct contact with the injured or damaged tissue. In actual fact, so-called cooling packs are already known, which make use of the endothermic solution reaction of a salt in water for cooling therearound, for example ammonium nitrate which takes heat from the environment when it is dissolved in water and thereby causes a substantial drop in temperature. However, cooling agents of this kind are inconceivable for use in a medical connection for the above-discussed cooling purposes because, like ammonium nitrate, they are toxic and corrosive or caustic so that there must be a fear of considerable damage in the event of coming into direct contact with the wound. Even if it is theoretically possible for such cooling agents to be protected from direct contact with the parts or areas of the body to be cooled, by suitable packaging of the cooling agents, nonetheless in practice this danger cannot be totally excluded, for example due to the possibility of damage to the packaging, so that the resulting risk cannot be accepted.
A cooling pack is also already known wherein a flexible container comprising for example plastic foil is filled with a chemical, the melting point of which is in the temperature range which is to be assumed by a part of a body to be cooled (German Offenlegungsschrift (laid-open application) No. 23 05 504). The selection of the chemical involved is such that it is changed into the solid condition by the action thereon of a cold source and, when the cooling pack is used on an object, it absorbs its latent heat of fusion therefrom. This cooling pack maintains a constant cooling temperature until it reaches its melting point at which it is converted back into a liquid condition. This cooling pack also presupposes that there will be available a cooling source for changing it from the liquid into the solid aggregate condition, and the chemicals proposed for this purpose are of a kind which makes them unsuitable for use in particular on open wounds, for medical purposes.